The goal of Project 1 is to determine the identity of pancreatic stem cells and their capacity to develop into beta-cells. Aim 1: Are pancreatic duct cells heterogeneous with regard to their potential to serve as stem/progenitor cells? Populations of duct cells with be separated using immunomagnetic beads and diphtheria toxin A ablation approach, and then analyzed to determine whether some preferentially express candidate genes. The populations could referent different phenotypes or possibly different stages of the same cells. Aim 2. Gene expression profiling if islet and ductal progenitor cell populations. Are these populations the same or complementary? NIPs are nestin-positive islet-derived progenitor cells and similar nestin-positive cells have been identified in the ducts, whereas ductal progenitors are derived from islet-depleted pancreatic digests after islet isolation. To determine whether NIPs and ductal progenitor populations are the same or complementary, we will perform gene expression profiles of these cells using multiplex RT-PCR, cDNA micro-arrays and Affymetrix gene chips. Aim 3. Test the in vivo differentiation potential for NIPS cells in the experimental partial pancreatectomy model of pancreatic regeneration and differentiation. A major objective of Project 1 is to obtain proof-of- concept that islet-derived stem/progenitor cells can successfully engraft differentiate into beta-cells in rodent models of diabetes, and cure the diabetes. Stem cells will be administered to rats at the time of partial pancreatectomy to determine whether the development of diabetes can be prevented.